GPU Implementation of DPSO-RE Algorithm for Parameters Identification of Surface PMSM Considering VSI Nonlinearity

In this paper, an accurate parameter estimation model of surface permanent magnet synchronous machines (SPMSMs) is established by taking into account voltage-source-inverter (VSI) nonlinearity. A fast dynamic particle swarm optimization (DPSO) algorithm combined with a receptor editing (RE) strategy is proposed to explore the optimal values of parameter estimations. This combination provides an accelerated implementation on graphics processing unit (GPU), and the proposed method is, therefore, referred to as G-DPSORE. In G-DPSO-RE, a dynamic labor division strategy is incorporated into the swarms according to the designed evolutionary factor during the evolution process. Two novel modifications of the movement equation are designed to update the velocity of particles. Moreover, a chaotic-logistic-based immune RE operator is developed to facilitate the global best individual (gBest particle) to explore a potentially better region. Furthermore, a GPU parallel acceleration technique is utilized to speed up parameter estimation procedure. It has been demonstrated that the proposed method is effective for simultaneous estimation of the PMSM parameters and the disturbance voltage (Vdead) due to VSI nonlinearity from experimental data for currents and rotor speed measured with inexpensive equipment. The influence of the VSI nonlinearity on the accuracy of parameter estimation is analyzed

Entropy-corrected new agegraphic dark energy in Horava-Lifshitz cosmology

We study the entropy-corrected version of the new agegraphic dark energy (NADE) model and dark matter in a spatially non-flat Universe and in the framework of Ho\v{r}ava-Lifshitz cosmology. For the two cases containing noninteracting and interacting entropy-corrected NADE (ECNADE) models, we derive the exact differential equation that determines the evolution of the ECNADE density parameter. Also the deceleration parameter is obtained. Furthermore, using a parametrization of the equation of state parameter of the ECNADE model as $\omega_{\Lambda}(z)=\omega_0+\omega_1 z$, we obtain both $\omega_0$ and $\omega_1$. We find that in the presence of interaction, the equation of state parameter $\omega_0$ of this model can cross the phantom divide line which is compatible with the observation.Comment: 20 pages, 2 figures, to appear in 'Astrophysics and Space Science

Export-market dynamics and the probability of firm closure: evidence for the United Kingdom.

This study presents the first empirical analysis of the determinants of firm closure in the United Kingdom with an emphasis on the role of export-market dynamics, using panel data for a nationally representative group of firms operating in all-market-based sectors during 1997–2003. Our findings show that the probability of closure is (cet. par.) significantly lower for exporters, particularly those experiencing export-market entry and exit. Having controlled for other attributes associated with productivity (such as size and export status), the following factors are found to increase the firm's survival prospects: higher capital intensity and TFP, foreign ownership, young age, displacement effects (through relatively high rates of entry of firms in each industry), and belonging to certain industries. Interestingly, increased import penetration (a proxy for lower trade costs) leads to a lower hazard rate for exporting entrants and continuous exporters, while inducing a higher hazard rate for domestic producers or those that quit exporting

Participation in export markets and the role of R&D: establishment-level evidence from the UK Community Innovation Survey 2005.

There is a strong expectation in the literature that exporting and innovation activities (particularly R&D) are strongly related, and that the need to be innovative is increasing over time due to globalization. In this study, we find that R&D is endogenous in a model that determines which British establishments enter export markets, and when such simultaneity is taken into account the strength of the export-innovation relationship is generally quite weak (especially in the nonmanufacturing sector). Rather, we find that the size of establishments and firms, foreign ownership, the extent of international co-operation and, most importantly, the industry sector to which the establishment belongs, are the most significant in explaining which establishments are able to overcome entry barriers into overseas markets

Determinants of firm exit from exporting : evidence for the UK.

This study seeks to understand to what extent new exporters are able to survive in international markets and whether exit from exporting is more likely to be associated with firm-level heterogeneity or more general factors such as trade costs and/or barriers to entry and exit (such as sunk costs). This study presents the first analysis undertaken for a nationally representative group of UK firms on the determinants of exit from exporting, using panel data covering all market-based sectors of the UK during 1997–2003. Our findings suggest that the probability of a firm ceasing to export is directly influenced by its productivity and other attributes associated with firm-level productivity differences (such as size and foreign ownership). Micro-finance factors, such as profitability and the ability to finance through long-term debt, play an additional role. Lastly, sectoral differences (e.g. industrial concentration) also help explain the firm’s exit decision, whilst trade costs lead to a higher probability of exiting from selling internationally

Evaluating the contribution of exporting to UK productivity growth: some microeconomic evidence.

This study assesses the contribution of exporting activities to aggregate productivity growth in the UK for all market-based sectors for the period 1996–2004, using a weighted FAME dataset. Based on decompositions of productivity growth, our findings suggest that, overall, exporting firms experience faster productivity growth than non-exporting firms and therefore contribute more to national productivity growth. In addition, aggregate productivity for exporters benefits from a large contribution from ‘continuing’ firms improving their productivity, as well as exporters that have been taken-over/merged or started-up as new firms. In contrast, most of the TFP improvement for non-exporters is attributable to lower productivity firms exiting, rather than from internal improvements or the productivity-enhancing impact of new firms

The impact of higher education institution-firm knowledge links on firm-level productivity in Britain.

This article estimates whether knowledge links with universities impact on establishment-level Total Factor Productivity (TFP). Using propensity score matching, the results show a positive and statistically significant impact although there are differences across production and nonproduction industries and domestically and foreign-owned firms